Display device

ABSTRACT

A display device having an insulating substrate on which transparent electrodes having display electrode portions and wiring electrodes portions are formed, and another substrate opposed to the insulating substrate. At a portion of the insulating substrate at which the wiring electrode patterns extend across a contour line of the opposing substrate, the wiring electrode patterns are set perpendicular to the end surface of the opposing substrate. Dummy patterns may be provided outside the opposite-end terminal patterns in the group of wiring electrode patterns. In the thus-arranged display device, when the wiring electrodes are plated after assembly of a display element, a short circuit cannot occur on the insulating substrate portion at which the wiring electrode patterns extend across the contour line of the opposing substrate. Pads for contact with a short check probe are arranged in a straight line on the insulating substrate. A low-priced straight probe can therefore be used for a short circuit check.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a display device in which wiringportions of transparent electrodes are metallized, to a display devicein which semiconductor chips are mounted based on a chip-on-glass (COG)method, and to a method for inspecting a display panel used in thedisplay device.

[0002] A manufacturing method has been devised for manufacture of aso-called COG type display device in which surfaces of terminalelectrodes of a display element are metallized by plating, and asemiconductor chip is placed on the metallized surfaces of theelectrodes. This method provides a simple means for reducing theresistance value of the terminal electrodes, and therefore achieves, ata low cost, a reduction in the frame area based on use of fine terminalpatterns as well as an improvement in connection reliability.

[0003]FIGS. 2A and 2B schematically illustrate a conventional COG typedisplay device. FIG. 2A is a top view of a glass substrate 1 on whichthe display device is formed, and FIG. 2B is a cross-sectional view ofthe display device.

[0004] Transparent electrodes formed of an indium tin oxide (ITO) filmare formed on the glass substrate 1. The transparent electrodes areformed by patterning on predetermined shapes according to the contentsto be displayed. Portions of the transparent electrodes are sorted asdisplay electrode portions 4 and wiring electrode portions 6 accordingto their functions. The glass substrate 1 and an opposing substrate 2opposed to the glass substrate 1 are attached to each other by a sealingmaterial 3, with a spacing of about 5 to 7 μm set therebetween. A liquidcrystal 5 is injected into the spacing and contained in the same in asealing manner, thus forming a liquid crystal panel.

[0005] Pads 7 are formed on terminal end of the wiring electrodeportions 6 corresponding to output and input terminal electrodes of asemiconductor chip. The wiring electrodes 6 are laid obliquely withrespect to a contour line of the display panel to connect the displayelectrode portions 4 and pads 7 respectively arranged with differentpitches. That is, on a portion of the glass substrate 1 at which thewiring electrodes 6 extend across an end surface of the opposingsubstrate 2, the wiring electrodes 6 are formed so as to be oblique withrespect to the end surface of the opposing substrate 2. Similarly, on aportion of the opposing substrate 2 at which wiring electrodes (notshown) on the opposing substrate 2 extend across an end surface of theglass substrate 1, the wiring electrode on the opposing substrate 2 areformed so as to be oblique with respect to the end surface of the glasssubstrate 1. As wiring electrodes 6, some electrode groups may be formeddepending upon electrode layout artwork. As described above, along anopposing substrate contour line 14 along which a plane defining the endsurface of the opposing substrate 2 meets the surface of the glasssubstrate 1, wiring electrodes 6 exist on some portions of the glasssubstrate 1 and no wiring electrodes 6 exist on the other portions ofthe glass substrate 1.

[0006] The wiring electrodes formed as described above are selectivelyplated by nonelectrolytic nickel plating. That is, the wiring electrodesexposed outside the liquid crystal panel (on the glass substrate 1outside the opposing substrate contour line 14) are selectively platedby nonelectrolytic nickel plating.

[0007] As described above, the wiring electrodes 6 are oblique withrespect to the opposing substrate contour line at the portion of theglass substrate 1 at which the wiring electrodes 6 extend across the endsurface of the opposing substrate 2. The plating liquid has differentangles of contact on the ITO surface and the glass substrate surface.That is, the plating liquid has a smaller angle of contact on the ITOsurface, and the ITO surface is easy to wet. In contrast, the platingliquid has a lager angle of contact on the glass surface than that onthe ITO surface, and the glass surface repels the plating liquid incomparison with the ITO surface. For this reason, the plating liquid canremain easily at a step formed by the glass substrate 1 and the opposingsubstrate 2 (on the glass substrate portion close to and outside the endsurface of the opposing substrate 2) and between an adjacent pair of thewiring electrodes, covering the glass portion where no wiring electrodeportion exists. In particular, as shown in FIG. 2A, plating liquid 9 canremain easily between the outermost wiring electrode in the wiringelectrode group and another of the wiring electrodes adjacent to theoutermost one. A bridge 10 of a nickel thin film can thus form along theperiphery of the mass of remaining plating liquid 9 between the wiringelectrodes.

[0008] After plating, therefore, it is necessary to perform a shortcircuit check with a probe or to check the existence/absence of such abridge and to identify a bridging place by image recognition or thelike. If one of the formed liquid crystal display elements has a bridge10, it is necessary to repair a bridged portion by using laser or thelike.

[0009] In the construction of the conventional liquid crystal displaydevice, as described above, a short circuit can occur easily betweenwiring electrodes at the time of plating after the assembly of thedisplay panel. Therefore, there is a need to check the existence/absenceof such a short circuit. However, a high-priced probe is required forchecking because the wiring electrode portions and the pads are arrangedwith small pitches.

SUMMARY OF THE INVENTION

[0010] In view of the above-described problems, it is an object of thepresent invention to provide a liquid crystal display device in whichthe possibility of occurrence of a short circuit between wringelectrodes is reduced, and in which a short circuit check can beperformed by using a low-priced straight probe.

[0011] To achieve this object, according to one aspect of the presentinvention, there is provided a liquid crystal display device having adisplay element in which, at a portion of an insulating substrate atwhich a bridge short circuit can occur particularly easily, and at whichwiring electrodes on the insulating substrate extend across an endsurface of an opposing substrate, the wiring electrodes are formed so asto be perpendicular to the end surface of the opposing substrate.

[0012] In another aspect of the present invention, an additional dummypattern is provided outside the wiring electrodes between which thepossibility of occurrence of a bridge short circuit is highest.

[0013] In still another aspect of the present invention, probe pads forcontact with a probe used for a short circuit check in the liquidcrystal display are formed by being arranged in a straight row such thatthe probe can be simple in structure and can be manufactured at a lowcost.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In the accompanying drawings:

[0015]FIG. 1A is a schematic top view of a glass substrate 1constituting a liquid crystal display element in accordance with a firstembodiment of the present invention;

[0016]FIG. 1B is a schematic cross-sectional view of the liquid crystaldisplay element shown in FIG. 1A;

[0017]FIG. 2A is a schematic top view of a glass substrate 1constituting a conventional liquid crystal display element;

[0018]FIG. 2B is a schematic cross-sectional view of the conventionalliquid crystal display element;

[0019]FIG. 3A is a schematic top view of a glass substrate constitutinga liquid crystal display element in accordance with a second embodimentof the present invention;

[0020]FIG. 3B is a schematic cross-sectional view of the liquid crystaldisplay element shown in FIG. 3A;

[0021]FIG. 4A is a schematic top view of a glass substrate constitutinga liquid crystal display element in accordance with a third embodimentof the present invention; and

[0022]FIG. 4B is a schematic cross-sectional view of the liquid crystaldisplay element shown in FIG. 1A.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The construction of a display device in accordance with a firstembodiment of the present invention will be described below. The displaydevice of the present invention has an insulating substrate on whichdisplay electrodes and wiring electrodes are formed, an opposingsubstrate opposed to the insulating substrate, and a display materialcontained in a spacing between the insulating substrate and the opposingsubstrate in a sealing manner. Each of portions of the wiring electrodesextending across a contour line of the opposing substrate is formedperpendicular to the contour line of the opposing substrate.

[0024] In the thus-arranged display device, when the wiring electrodesare metallized by plating, the possibility of occurrence of a shortcircuit between the wiring electrodes due to a residue of a platingliquid in a place where the wiring electrodes extend across the opposingsubstrate end surface is low.

[0025] A display device in accordance with a second embodiment of thepresent invention includes: an insulating substrate on which displayelectrodes and a plurality of wiring electrodes are formed; an opposingsubstrate opposed to the insulating substrate; and a display materialcontained in a spacing between the insulating substrate and the opposingsubstrate in a sealing manner. A dummy electrode is provided outside theoutermost one of the wiring electrodes.

[0026] In the thus-arranged display device, even if a shortingphenomenon occurs at the outer end of the wiring electrode array whenthe wiring electrodes are metallized by plating, there is substantiallyno possibility of occurrence of electrical shorting and there is nofunctional problem, since the dummy electrode is provided at theoutermost end of the wiring electrode group.

[0027] Further, the spacing between the dummy electrode and theoutermost wiring electrode is equal to or smaller than the spacingbetween the outermost wiring electrode and the inner wiring electrodenext to the outermost wiring electrode.

[0028] Thus, a shorting phenomenon, if any, occurs only between thedummy electrode and the adjacent wiring electrode, and occurrence of ashort circuit between the inner wiring electrodes can be prevented.

[0029] A display device in accordance with a third embodiment of thepresent invention includes: an insulating substrate on which displayelectrodes are formed; an opposing substrate opposed to the insulatingsubstrate; a display material contained in a spacing between theinsulating substrate and the opposing substrate in a sealing manner; asemiconductor chip for supplying signals to the display electrodes; agroup of pads arranged on the insulating substrate so as to correspondto connection terminals of the semiconductor chip; and a group of checkpads arranged in a straight row.

[0030] The display device is thus arranged to be capable of beingchecked with a straight probe, and such a probe can be manufactured at alow cost. Also, a standard probe can be designed to check variousdisplay devices formed in accordance with the present invention.

[0031] Some of the group of pads corresponding to the semiconductor chipterminals form a part of the group of check pads. The display device isthus arranged to be checked with a straight probe and to reduce the sizeof the insulating substrate by setting the mounted position of thesemiconductor chip closer to the step formed by the substrates (in thevicinity of a line along which a plane defining the end surface of theopposing substrate meets the surface of the insulating substrate).

[0032] Embodiments of the present invention will be described below withreference to the accompanying drawings.

Embodiment 1

[0033]FIGS. 1A and 1B schematically show an example of a liquid crystaldisplay element of the present invention. A glass substrate 1 is used asan insulating substrate, and transparent electrodes formed of an ITOfilm are formed on a surface of the glass substrate 1. FIG. 1A is a topview of the glass substrate 1 constituting the liquid crystal displayelement, and FIG. 1B is a cross-sectional view of the liquid crystaldisplay element. The transparent electrodes are formed by patterning onpredetermined shapes according to display contents to be displayed.Portions of the transparent electrodes are sorted as display electrodeportions 4 and wiring electrode portions 6 according to their functions.

[0034] If a black-and-white full dot matrix type liquid crystal displaydevice is formed, the electrode pitch between the display electrodeportions 4 is about 0.3 to 0.4 mm. On the other hand, the electrodepitch of input and output terminals of a semiconductor chip mounted inthe COG manner is about 0.05 to 0.10 mm. Therefore, it is necessary forthe wiring electrodes 6 connecting the display electrode portions 4 andpads 7 corresponding to the terminal electrodes of the semiconductorchip to fill the difference between the pitches of the displayelectrodes 4 and the pads 7. In this embodiment, the group of wiringelectrodes 6 are formed on the glass substrate 1 so as to beperpendicular to an end surface of an opposing substrate 2 at a portion8 of the glass substrate 1 at which the wiring electrodes 6 extendacross the end surface of the opposing substrate 2. If a semiconductorchip is mounted on the opposing substrate 2, wiring electrodes (notshown) are also formed by patterning on the opposing substrate 2 so asto be perpendicular to an end surface of the glass substrate 1 at aportion of the opposing substrate 2 at which the wiring electrodesextend across the end surface of the glass substrate 1.

[0035] Thus, the wiring electrodes 6 are formed by patterning on theglass substrate 1 so as to be each perpendicular to the end surface (acontour line of the opposing substrate) of the opposing substrate 2 atthe portion 8 at which the wiring electrodes 6 extend across the endsurface of the opposing substrate 2 (the contour line of the opposingsubstrate). Therefore, a plating liquid cannot remain easily on theportion 8 of the glass substrate 1 at which the wiring electrodes 6extend across the end surface of the opposing substrate 2, thuspreventing occurrence of bridging of nickel thin film between the wiringelectrodes 6.

[0036] The method of manufacturing a display device having theabove-described configuration will be described. Two insulatingsubstrates on which display electrodes and wiring electrodes are formedby patterning are attached to each other by a sealing material 3, with aspacing of 5 to 7 μm set therebetween. A liquid crystal 5 is injectedinto the spacing and contained in the same in a sealing manner. If aplurality of groups of display elements for a plurality of displaydevices are arranged on the insulating substrates, corresponding liquidcrystal panels may be separated by forming scribe lines in theinsulating substrates along the contours of the liquid crystal panels byusing a superhard roll, a diamond cutter or the like, before the liquidcrystal is injected. As described above, all the wiring electrodes 6 areformed on the glass substrate 1 so as to be perpendicular to the endsurface of the opposing substrate 2 at the portion 8 at which the wiringelectrodes 6 extend across the end surface of the opposing substrate 2.

[0037] Next, the wiring electrode portions on the glass substrate 1exposed outside the liquid crystal panel are selectively plated bynonelectrolytic nickel plating. More specifically, the liquid crystalpanel is washed by water and is immersed in an alkaline solution, suchas a sodium hydroxide solution, for degreasing. Based on an ordinarymethod, a precious metal catalyst, such as palladium, is attached to thesurfaces of the wiring electrodes, and the liquid crystal panel isimmersed in a nonelectrolytic nickel liquid containing phosphoric acidused as a reducing agent. A nickel-phosphorus coat (hereinafter referredto as nickel coat or nickel film) is thereby precipitated on the wiringelectrodes. At this time, the plating liquid does not remain at the stepformed by the insulating substrates, since the wiring electrodes 6 onthe glass substrate 1 are perpendicular to the end surface of theopposing substrate 2 at the portion of the glass substrate 1 at whichthe wiring electrodes 6 extend across the end surface of the opposingsubstrate 2. Therefore, no nickel thin film bridge forms between theconnecting electrodes 6. The same can also be said with respect toconnection electrodes on the opposing substrate 2.

[0038] Then, a gold coat is precipitated on the nickel coat. Morespecifically, after washing in water which follows nickel plating, theliquid crystal panel is immersed in a substitution-type nonelectrolyticgold plating liquid to substitute the surface of the nickel coat formetal gold, thereby forming a gold coat. After washing in water, thecoat is annealed at 120° C. for an hour. By annealing, the hardness andadhesion of the plating film are improved.

[0039] On the liquid crystal panel in which the surfaces of the terminalelectrodes of the display element are metallized by plating, asemiconductor chip for applying drive voltages to the display electrodesis mounted by being connected to pads 7 on the glass substrate 1 by aconnecting material, such as anisotropic conductive film (ACF), based onan ordinary method. Before mounting, a polarizing plate is attached, ifnecessary, over the display area of the insulating substrates whereelectrode patterns are formed. In the above-described manner, a displaydevice is obtained in which semiconductor chips are mounted on the glasssubstrate based on the COG method.

[0040] If the surfaces of transparent electrodes are metallized asdescribed above, it is preferable to use an ITO film formed by anelectron beam (EB) method to have a rough surface. This is because ametallic catalyst can attach easily to a rough ITO film surface, andbecause such an ITO film can therefore be metallized more effectivelythan an ITO film formed by sputtering to have a smooth surface. That is,as the transparent electrode, an ITO film formed by an EB method ispreferred rather than an ITO film formed by sputtering.

Embodiment 2

[0041]FIGS. 3A and 3B schematically show a liquid crystal displayelement in accordance with a second embodiment of the present invention.FIG. 3A is a top view of a glass substrate 1, and FIG. 3B is across-sectional view of the liquid crystal display element.

[0042] Transparent electrodes 4 formed of an ITO film are formed on asurface of the glass substrate 1 provided as an insulating substrate.The transparent electrodes 4 are formed by patterning on predeterminedshapes, and portions of the transparent electrodes are sorted as displayelectrode portions 4, wiring electrode portions 6, and pads 7 accordingto their functions.

[0043] Since the pitch with which the pads 7 corresponding to terminalelectrodes of a semiconductor chip and the pitch with which the displayelectrode portions 4 are arranged differ from each other, the wiringelectrode portions 6 that connect the pads and the display electrodeportions 4 are patterned obliquely. That is, on a portion of the glasssubstrate 1 at which the wiring electrode portions 6 extend across anend surface of an opposing substrate 2, the wiring electrode portions 6are formed obliquely with respect to the end surface of the opposingsubstrate 2. Similarly, wiring electrodes (not shown) on the opposingsubstrate 2 are also patterned obliquely with respect to an end surfaceof the glass substrate 1 at a portion of the opposing substrate 2 atwhich the wiring electrodes extend across the end surface of the glasssubstrate 1. In this embodiment, a dummy electrode 11 is formed outsidethe wiring electrodes 6.

[0044] Ordinarily, as described above, a plating liquid 9 can remaineasily between the outermost connecting electrode in the electrode groupand another of the connecting electrodes adjacent to the outermost oneon the glass substrate portion in the vicinity of the end surface of theopposed electrode, and a bridge 10 of a nickel thin film is liable toform along the periphery of the mass of remaining plating liquid 9. Inthe arrangement of the present embodiment, a nickel thin film bridge 10may form between the dummy electrode 11 outside the electrode group andthe adjacent connecting electrode 6. However, since one of the twoelectrodes between which a bridge may form is a dummy electrode, thereis substantially no possibility of occurrence of electrical shorting,and there is no functional problem.

[0045] As wiring electrodes 6, some electrode groups may be formeddepending upon electrode layout artwork. For example, if a plurality ofsemiconductor chips are mounted on the glass substrate, a plurality ofcorresponding groups of wiring electrodes are formed by patterning. Insuch a case, dummy electrodes may be formed outside the opposite-endwiring electrodes in each group.

[0046] The distance d1 between the dummy electrode and the wiringelectrode adjacent to the dummy electrode may be equal to the distanced2 between the outermost wiring electrode (the wiring electrode adjacentto the dummy electrode) and the inner wiring electrode next to theoutermost wiring electrode, or may be set to a value smaller than d2 tomake the dummy electrode more effective.

[0047] Preferably, the dummy electrode 11 is formed parallel to theoutermost wiring electrode. Preferably, the dummy electrode 11 is formedso that at least the inner adjacent pair of the lengthwise patterncontour lines of the wiring electrode and the dummy electrode areparallel to each other.

[0048] The width of the dummy electrode may be the same as or largerthan the width of the wiring electrode. Also, a plurality of dummyelectrodes may be provided. If a plurality of dummy electrodes areformed, the distance between the outermost dummy electrode and the groupof wiring electrodes is substantially large, so that the possibility ofoccurrence of a short circuit between the wiring electrodes is reduced.

[0049] Preferably, the area of the glass surface outside the outermostwiring electrode is reduced by increasing the width of the dummyelectrode or by forming a plurality of dummy electrodes, therebyincreasing areas occupied by transparent electrodes. If the length ofthe dummy electrode is so small that the dummy electrode only reaches apoint on the glass substrate in the vicinity of the end surface of theopposing substrate, the effect of the dummy electrode is inadequate.Accordingly, it is necessary to sufficiently extend the dummy electrode11 outward from the end surface of the opposing substrate 2 (toward thecontour line of the glass substrate), as shown in FIG. 3A.

Embodiment 3

[0050]FIGS. 4A and 4B schematically show a liquid crystal displayelement in accordance with a third embodiment of the present invention.FIG. 4A is a top view of a glass substrate 1 constituting the liquidcrystal display element, and FIG. 4B is a cross-sectional view of theliquid crystal display. element. Transparent electrodes patterned onpredetermined shapes are formed on a surface of the glass substrate 1used as an insulating substrate. Portions of the transparent electrodesare sorted as display electrode portions 4, wiring electrode portions 6,and a pad group 12 according to their functions. Pads in the pad group12 are formed so as to correspond to terminal electrodes of asemiconductor chip. Ordinarily, terminal electrodes of semiconductorchips are disposed so as to have a tetragonal configuration. If thesemiconductor chip to be mounted has such a terminal electrodeconfiguration, the pad group 12 is also arranged in a correspondingtetragonal configuration, as illustrated. The terminal electrodes of thesemiconductor chip include input terminals for inputting signals to theinternal circuit of the semiconductor chip, and output terminals foroutputting drive signals to the display electrodes. Accordingly, the padgroup 12 formed on the glass substrate 1 includes pads 7, which arearranged so as to correspond to the output terminals of thesemiconductor chip, and input pads 15, which are formed so as tocorrespond to the input terminals of the semiconductor chip. wiringelectrode portions 6 are formed by patterning to electrically connectthe pads 7 and the display electrode portions 4. Input wiring electrodes17 are also formed by patterning to electrically connect the input pads12 and external connection terminals 16 for connection to an externalcontroller.

[0051] In this embodiment, check pads 18 are provided between thedisplay electrode portions 4 and the pads 7. The wiring electrodeportions 6 are provided for electrical connection between the displayelectrode portions 4 and the check pads 18, and for electricalconnection between the check pads 18 and the pads 7. The check pads 18are arranged in a straight row to form a check pad group 13. Ashort-circuit check probe is brought into contact with each check pad inthe check pad group 13 to check a short circuit between the electrodes.Since the check pad group 13 has a straight configuration, the checkprobe may be straight in shape, so that the probe itself can bemanufactured at a low cost. Also, for alignment of the check pads 18 andthe check probe, only positioning in the horizontal direction as viewedin FIG. 4A (parallelizing adjustment) may suffice. Alignment of thisprobe can be easily performed in comparison with alignment of atetragonal probe, which requires parallelizing adjustment in twodirections. In use of the probe, liquid crystal drive voltages may beapplied through the probe between the display electrodes 4 on the glasssubstrate 1 and the display electrodes on the opposing substrate 2 tocheck display appearances or the like.

[0052] Further, the arrangement may be such that the pitch forarrangement of check pads and the number of check pads are standardized,a corresponding standard probe is prepared, and check pad group 13 isprovided on the glass substrate 1 in accordance with this standard,thereby ensuring that, even if the configuration of semiconductor chipterminal electrodes is changed by a change of the chip type or the like,the same check probe, i.e. the standard probe, can be used to check ashort circuit between electrodes without change in the check probe.

[0053] In the example of configuration shown in FIG. 4A, the check padgroup 13 is formed by arranging the check pads 13 in a straight row incombination with a certain number of pads in the pad group 12. If someof pads 7 are also used as check pads in the above-described manner, theadvantage of standardization of the probe may be lost. However, such anarrangement is effective in satisfying a demand for minimizing the sizeof the glass substrate 1. That is, to bring the probe into contact withthe check pads, the check pad group 13 needs to be formed at a certaindistance from the end surface of the opposing substrate 2. If no pads 7are used as check pads, the check pad group 13 is provided internallyrelative to the pads 7. In such a case, the position at which thesemiconductor chip is mounted (i.e., the position of the pad group 12)is shifted toward the edge of the glass substrate 1, and the size of theglass substrate 1 is correspondingly increased.

[0054] The method of manufacturing the display device by using the glasssubstrate having transparent electrodes patterned on the above-describedconfiguration is the same as that in the above-described embodiment, andthe description for it will be omitted.

[0055] This embodiment has been described with respect to the pad group12 including pads 7 arranged so as to correspond to output terminals ofa semiconductor chip, and input pads 15 formed so as to correspond toinput terminals of the semiconductor chip. In the above-described firstand second embodiments, however, patterns may be formed in the samemanner as those in this embodiment, for the mounting of a semiconductorchip on the glass substrate. Power supply pads in the input pads 15 andcorresponding wiring portions, in particular, need to be metallized.

[0056] An example of a supertwisted nematic (STN) type of liquid crystaldisplay device has been described as each of the first to thirdembodiments of the present invention. However, the liquid crystal in thedisplay device of the present invention may be of any other type, e.g.,a twisted nematic (TN) type or a polymer dispersion type. If a patternconfiguration which is a combination of the configuration in the firstembodiment and the dummy pattern described in the description of thesecond embodiment is used, occurrence of a short circuit bymetallization can be prevented more reliably. Also, the check pad groupdescribed with respect to the third embodiment may be added to theconfiguration of the first or second embodiment to enable metallizationwithout a risk of short-circuiting as well as to facilitate checking.

[0057] The display device of the present invention may be either a typeof COG display device in which connection electrodes on the opposingsubstrate are connected by common members in the liquid crystal panel topoints on the other insulating substrate, or another type of COG displaydevice in which semiconductor chips are mounted on the two insulatingsubstrates, as are those in the above-described embodiments.

[0058] In the display device of the present invention, the possibilityof occurrence of a short circuit between connecting electrodes,resulting in a functional failure, can be reduced. Also, a dummyelectrode is provided to avoid a functional failure even when a bridgingshort circuit occurs. A straight row of check pads is provided and,therefore, a straight probe suffices for checking. Such a probe can bemanufactured at a low cost. At the time of checking, alignment of thecheck probe with the check pads requires only parallelizing adjustmentin one direction and can therefore be performed more easily incomparison with alignment of a tetragonal probe requiring parallelizingadjustment in two directions. The desired accuracy thereof can be easilymaintained during checking, and the tooling can be easily changed.

What is claimed is:
 1. A display device comprising: an insulatingsubstrate on which display electrodes and wiring electrodes are formed;an opposing substrate opposed to said insulating substrate; and adisplay material contained in a spacing between said insulatingsubstrate and said opposing substrate in a sealing manner, wherein saidwiring electrodes are metallized by plating, and each of portions ofsaid wiring electrodes extending across a contour line of said opposingsubstrate is formed perpendicular to the contour line of said opposingsubstrate.
 2. A display device comprising: an insulating substrate onwhich display electrodes and wiring electrodes are formed; an opposingsubstrate opposed to said insulating substrate; and a display materialcontained in a spacing between said insulating substrate and saidopposing substrate in a sealing manner, wherein said wiring electrodesare metallized by plating, and a dummy electrode is provided outside theoutermost one of said wiring electrodes.
 3. A display device accordingto claim 2, wherein the spacing between said dummy electrode and theoutermost wiring electrode is equal to or smaller than the spacingbetween the outermost wiring electrode and the inner wiring electrodenext to the outermost wiring electrode.
 4. A display device according toclaim 2, wherein said wiring electrodes comprise a plurality of wiringelectrode groups each formed of a plurality of wiring electrodes, anddummy electrodes are provided outside the opposite-end wiring electrodesin each of said wiring electrode groups.
 5. A display device accordingto claim 2, wherein said dummy electrode is formed parallel to theoutermost wiring electrode.
 6. A display device comprising: aninsulating substrate on which display electrodes are formed; an opposingsubstrate opposed to said insulating substrate; a display materialcontained in a spacing between said insulating substrate and saidopposing substrate in a sealing manner; a semiconductor chip forsupplying signals to said display electrodes; a group of pads arrangedon said insulating substrate so as to correspond to connection terminalsof said semiconductor chip; a group of check pads provided between saiddisplay electrodes and said group of pads; and wiring electrodes forestablishing electrical connections between said display electrodes andsaid group of check pads corresponding to the semiconductor chipterminals, and electrical connections between said group of check padsand said group of pads corresponding to the semiconductor chipterminals, wherein said group of check pads are arranged in a straightrow.
 7. A display device according to claim 6, wherein some of saidgroup of pads corresponding to the semiconductor chip terminals form apart of said group of check pads.